This invention pertains to a contact assembly for low-voltage circuit breakers, specifically current-limiting circuit breakers with a two-arm contact lever which rotates around a central rotary axis, with the lever equipped at its ends on opposite sides of a longitudinal axis crossing the rotary axis with one contact piece on each side and having a biasing spring assigned to each lever arm.
A contact assembly of the above specified said type is disclosed in German Offenlegungsschrift No. 2,157,927. This contact assembly, in principle, has the advantage that no flat flexible conductor is necessary in the current path of the switch, since the two-arm contact lever bridges two fixed-mounted counter-connection pieces. Thus, when switching, two disconnect points connected in series are created. In conjunction with the relatively low energy requirement of a rotating lever device, one has the prerequisites for a high breaking capacity.
Even with these advantages, however, there are mechanical problems. In particular, it is difficult to assure the constancy of contact forces at the two disconnect points which is absolutely required for proper long-term operation. Moreover, fairly difficult problems are raised by the placement of the biasing springs and the transmission of the driving force into the contact lever. Accordingly, it will be appreciated that it would be highly desirable to provide a contact assembly which assures constancy of contact forces.
It is an object of the present invention to provide a contact assembly for a circuit breaker.
Another object of the invention is to provide a contact assembly which assures constancy of contact forces.